This invention relates to novel aqueous coating compositions which utilize polyethylene terephthalate (PET) as a raw material for producing the film-forming resin for such coatings. Most preferably, the PET is recycled or reclaimed PET from plastic articles such as two-liter beverage bottles.
Plastics such as PET account for about 7-8 weight percent, and about 20 volume percent, of the world's solid waste. As a result, much legislation has been proposed and/or adopted requiring the recycling of plastics.
PET is the primary ingredient in plastic articles such as two-liter beverage bottles and the like. In the U.S., PET is the plastic most often recycled. The biggest uses for recycled PET are as fibers in carpeting and insulation. Recycled PET is also used in bathroom equipment and blow-molded bottles.
Processes for recycling PET beverage bottles into usable raw materials for manufacturing unsaturated polyester resins are known. For example, Eastman Chemicals Publication No. N-262A entitled Unsaturated Polyester Resins Based on Reclaimed Polyethylene Terephthalate (PET) Beverage Bottles, Calendine et al. (1984), teaches a process for converting PET beverage bottles into useful intermediates for the synthesis of unsaturated polyesters. The unsaturated polyesters are further taught as useful as raw materials for producing unreinforced clear castings and fiberglass reinforced laminates.
A second Eastman Chemicals Publication, No. N-292B, entitled Aromatic Polyols From Reclaimed Polyethylene Terephthalate, (1987) teaches the reclamation of PET for production of aromatic polyester polyols which are useful in making rigid polyurethane polyisocyanurate foams.
U.S. Pat. No. 4,223,068 (Carlstrom et al.) teaches the use of the digestion product of polyalkylene terephthalate scraps with organic polyol for the production of rigid polyurethane foams.
U.S. Pat. No. 4,417,001 (Svoboda et al.) teaches the production of low smoke isocyanurate modified polyurethane foams which are prepared from polyols which are the digestion product of digesting polyalkylene terephthalate scraps and organic polyols.
U.S. Pat. No. 4,048,104 (Svoboda et al.) teaches the preparation of polyisocyanate prepolymers and polyurethane adhesives and foams wherein the prepolymers are prepared by reacting organic polyisocyanate with polyols which are the digestion product of polyalkylene terephthalate scraps and organic polyols.